Matrix acidizing has become a popular technique in the oil industry to enhance productivity. The process involves injecting acid into the rock formation to dissolve certain minerals, thereby increasing permeability and improving fluid flow. One acid used in matrix acidizing is hydrofluoric (HF) acid, but its hazardous nature and low penetration depth have led researchers to explore alternative acids such as fluoroboric acid (HBF4).
Compared to HF acid, HBF4 can penetrate deeper into the rock formation and has the ability to stabilize fines (tiny particles) by binding them to the pore surface. However, there is a lack of mathematical models that can accurately design and evaluate HBF4 treatments.
In a recent study published in the Journal of Petroleum Science and Engineering, a novel mathematical model was introduced that takes into account the chemical kinetics and equilibrium aspects of important reactions and fluid flow inside the reservoir rock. The model was validated through laboratory experiments and can be used to optimize HBF4 treatments.
The authors identified three benefits of their approach to modeling. First, it reduces the total number of chemical reactions taking place, which greatly simplifies computational complexity while maintaining reasonable accuracy. Second, the model considers the effects of reservoir heterogeneity on fluid flow and reaction rates. Finally, the model allows for the evaluation of the acid’s effectiveness in removing various minerals from the rock formation.
The researchers conducted experiments to validate their model using sandstone cores. They observed that the model accurately predicted the dissolution of minerals such as calcite, which is typically found in carbonate reservoirs. The results showed that HBF4 was able to dissolve calcite at a faster rate than HF acid.
The model also predicted the effectiveness of HBF4 in stabilizing fines in the rock formation. Fines can clog pores and reduce permeability, so stabilizing them can enhance fluid flow. The researchers found that HBF4 was able to bind fines to the pore surface and reduce their mobility, which is essential for maintaining permeability.
Overall, the study provides a reliable model for designing and evaluating HBF4 matrix acidizing treatments. The researchers hope that their work will encourage the adoption of HBF4 as an alternative acid for matrix acidizing in the industry.
In conclusion, the oil industry continues to seek new and innovative approaches to enhance productivity and maximize recovery. Matrix acidizing with HBF4 has shown promise as a safer and more effective alternative to HF acid. The development of a validated mathematical model for HBF4 treatments provides a valuable tool for designing and evaluating acidizing treatments and optimizing well performance.